The Infant Studies Core supports all projects involved in testing human infant subjects (Projects 2, 3, 4, 5, 6, and 7). The main purpose of this core unit is to procure infant subjects and maintain a database that contains a list of interested subjects along with the pertinent data on each subject. The Core plays all subject fees and incentives to encourage parents to bring their infants in for testing. A byproduct of the database is that it allows us to restrict the amount of testing done on any one infant, and allows us to coordinate the testing of individual infants when more than one team is interested in testing. A third purpose of the Infant Core is to hire consultants on a case-by-case basis to aid in developmental data analyses. The Infant Subject Pool (ISP) works in conjunction with a local baby diaper service. Postcards soliciting the infants' participation are distributed to parents of prospective subjects. Parents are asked to fill out and return the postcards. Approximately 10% of all postcards distributed are returned to the ISP. From the postcard responses, data pertaining to the infants are entered into the computer. When a particular investigator is interested in testing infants, they make a request to the ISP for a certain number of infants of a particular age. Lists containing infants' names and telephone numbers are made available to the investigator making the request. Utilizing these lists, investigators telephone the parents of infant subjects, and arrange testing dates. Upon completion of testing, subjects are paid a nominal fee for their participation. The ISP database is a rich resource containing, in an average week, the names of 20 newborns, and an additional 40 infants in each of the age ranges from 1 to 6 months. The annual number of infants recruited through these methods varies for each project, but the total for all projects is approximately 2000 per year. Listings of infants are kept for a number of years, so that older children may be recruited. The ISP is managed by two assistants under Kuhl's direction. These individuals collate data on infants, update databases containing pertinent data about infants, and generate listings of infants in the database.